Air distribution for an air seeder

ABSTRACT

An air distribution apparatus has a manifold body, and ports defined through walls thereof, with a delivery conduit connected to each port. A port valve is configured to connect and disconnect the delivery conduit to the interior of the manifold body. A supply conduit delivers a product air stream with agricultural products entrained therein to the interior of the manifold body. The supply conduit extends vertically up from the manifold to a curved elbow and then extends horizontally from the elbow. An exhaust orifice is defined in the inner radius of the elbow. When an exhaust valve is open, a selected flow of pressurized air flows from the supply conduit through the exhaust orifice. The port valve and exhaust valve are controlled such that when the port valve closes, the exhaust valve opens. The exhaust air can be directed into the delivery conduits to clear product therefrom.

This invention is in the field of agricultural air seeders and inparticular an air distribution apparatus with valves on the ports tocontrol product distribution and an exhaust to maintain criticalvelocity of the air stream.

BACKGROUND

Agricultural air seeders include generally an implement frame and aplurality of furrow openers spaced across a width of the frame, andmovable to a lowered operating position where the furrow openers engagethe ground to create furrows as the frame moves along a field.Agricultural products such as seed, fertilizer, and the like are carriedin tanks mounted on the frame or a cart pulled with the frame anddistributed to the furrow openers by a product distribution system whereone or more fans create one or more air streams and metering devicesdispense the agricultural products into the air streams and the productsare carried through an air distribution network made up of conduits andmanifolds to the furrow openers, and then into the furrows. Furrowopener assemblies often create two (or more) separate furrows, andseparate air streams carrying different agricultural products areconnected so as to deposit the different products in the separatefurrows.

There are different types of product distribution systems used onpresent day air seeders. In a Class A product distribution system, allagricultural products destined for a given furrow are metered into asingle air stream in a primary supply conduit connected to a primarymanifold. Such manifolds are generally a thin cylinder with an inlet ina top or bottom of the cylinder connected to the supply conduit toreceive the air stream carrying agricultural products, and a number ofoutlet ports equally spaced around a circumferential wall. Flat fanmanifolds are also known where the supply conduit directs the productair stream into one end of the a flat manifold body which divides theproduct air stream into channels with ports at the ends of the channelson the opposite end of the manifold body. Delivery conduits areconnected to each port to carry the air stream further downstream toanother manifold or to a furrow opener as the case may be.

In a Class A product distribution system the primary manifold providesprimary division of the air stream and the agricultural products carriedtherein by dividing and directing the air stream into a number ofdifferent delivery conduits, each of which is in turn connected to asecondary manifold. The secondary manifold provides secondary divisionof the air stream and the agricultural products carried therein bydividing and directing the air stream into a number of differentsecondary conduits, each of which is connected to a furrow opener todirect the air stream, and the agricultural products carried therein,into a selected furrow.

In a Class B product distribution system the metering device itself isdivided into a number of sections such that primary division of theagricultural products takes place prior to the products entering the airstream. Each conduit from a meter section is connected to a manifoldwhich provides secondary division of the air stream and the agriculturalproducts into a number of different secondary conduits, each of which isconnected to a furrow opener as in the Class A system.

In a Class C system, all division of the agricultural products takesplace at the metering device. The metering device is divided into anumber of sections equal to the number of furrow openers, and a singleconduit connects each meter section with each furrow opener.

Present day air seeders are often 80 or more feet wide, and a problemarises when a strip of a field to be seeded is much narrower than theseeder, as a considerable width of the field will be overlapped andseeded twice. It is most undesirable to leave even a narrow strip of afield unneeded as, without crop competition, weeds will flourish in thestrip providing seed for future years weed growth. Seeding the adjacentfield area twice however wastes valuable seed and fertilizer, and thecrop on the twice seeded field area generally has reduced yield and/orquality.

Thus it is desirable to provide a means to stop the delivery ofagricultural products to furrow openers in the overlap area by providingindividual control of the delivery of agricultural products to a numberof different sections of furrow openers across the width of the airseeder. U.S. Pat. No. 7,690,440 to Dean et al. discloses a Class Bproduct distribution system where the metering device is divided into anumber of sections, and where gates are provided at each meter sectionthat may be opened or closed to start or stop product flow from eachmeter section. The air seeder is configured so that each meter sectionsupplies agricultural products to a downstream manifold and from thereto furrow openers that are laterally arranged in order across a sectionof the width of the seeder so that stopping product flow to any manifoldstops product flow to a section of the air seeder. Thus as the strip offield to be seeded narrows to less than the width of the air seeder,product delivery is stopped to sections of the air seeder passing overpreviously seeded ground.

U.S. Pat. No. 7,555,990 to Beaujot takes a different approach byproviding gates on the outlet ports of the manifolds. The describedsystem has a single manifold downstream from the metering device, andgates are provided on each port of the manifold. Each port can thus beopened or closed, such that the delivery of the air stream with theentrained agricultural products to each furrow opener can be stopped orstarted. In one version of the Beaujot system, each delivery port ispaired with a corresponding recirculating port that is connected to aconduit to carry product that would ordinarily be carried to the furrowopener back to the tank containing the particular agricultural product.Thus when a port is closed, the corresponding recirculating port isopened and product is carried back to the tank from which it came.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an air distributionmanifold apparatus for an air seeder that overcomes problems in theprior art.

Thus in the prior art sectional control systems the delivery ofagricultural products to each section of furrow openers can becontrolled before the products enter the product air stream by stoppingand starting the metering devices feeding the products into the airstream as in the system of Dean et al, or after the products haveentered the air stream by opening and closing the ports on a manifold asin the system of Beaujot.

When some of the manifold ports are closed, the flow of air through thedownstream delivery conduits connected to the furrow openers is shut offand the air stream entering the manifold then must flow out through theopen ports such that an increased amount of air flows out each of theopen ports. As the number of closed ports increases, more and more airtries to flow through the open ports and back pressure in the manifoldincreases. With the fans most commonly used in air seeders to generatethe air streams used for distributing agricultural products throughconduits, as the back pressure in the conduits increases, the volume ofair moved decreases, and the velocity of the moving air decreases.

Thus in the system of Beaujot, as back pressure in the manifoldincreases, the volume of the air stream entering the manifold isreduced, and the velocity of the air flowing through the supply conduitfeeding the manifold is reduced. The air stream must move through thesupply conduit at a minimum velocity that sufficient to keep theagricultural products entrained in the air stream suspended therein.This critical velocity will be higher in a vertical section of thesupply conduit than in a horizontal section, as the air stream must movethe agricultural products upward against the force of gravity as opposedto moving the product laterally.

If the velocity drops below this “critical” velocity, the particles ofagricultural product will drop out of the air stream. Thus in theBeaujot system, as ports are closed the velocity of the air stream willat some point fall below the critical velocity, the agriculturalproducts will start to drop out of the air stream, and lay in the bottomof the supply conduit.

Constant volume blowers are also available for air seeders. Unlike thecommonly used fans, where as the pressure in the conduits increases thevolume of air moved decreases, these blowers provide a constant volumeof air as the pressure downstream rises. This will maintain the criticalvelocity of the air stream in the supply conduit since the same volumeof air will be moving therethrough. If a constant volume of air entersthe manifold, however it must leave the manifold through whatever portsare open. As the number of open ports decreases, more air must flowthrough each open port and the downstream delivery conduit connectedthereto, and the speed of the air stream in these delivery conduits willthus increase.

A well known problem in air seeders is that when the speed of the airstream to the furrow openers is excessive, the agricultural productscarried in the air stream can be blown out of the furrow, or can betravelling so fast that they bounce out of the furrow. Thus as ports areclosed, the speed of the air stream in the delivery conduits increases,and at some point an unacceptable amount of agricultural products willnot be placed in the furrows.

Also in the Beaujot system, as ports are closed the metered rate ofdispensing product into the air stream must be reduced proportionally tokeep the application rate constant. In order to accomplish this with thesingle meter disclosed, a single large manifold is shown, whichapparently feeds all the furrow openers.

A further problem arises when a port is closed and the flow of airthrough the downstream delivery conduits connected to the furrow openersis shut off. These delivery conduits very often do not slope down allthe way from the manifold to the furrow opener, but have low areas wherethe conduit dips down and then rises. When the manifold ports areblocked by the gates, the air is substantially instantly cut off andagricultural products in the downstream conduit are no longer carriedalong by the air stream but simply fall down, and can thus gather intoone of these low areas and block the conduit. Then when the port gate isopened again the air stream will not flow through the blocked conduitand the furrow opener will receive no product.

In some prior art systems the air stream carrying the agriculturalproducts is directed back to the tanks carry the products however theconduits downstream from the closed port are still cut off from any airstream. This return to tank method may work when a single granularproduct is metered into an air stream, but will not work when two ormore products have been metered together into the same airstream. Thereturned product is then mixed together and cannot be separated andreturned to the tank it was metered from.

In a first embodiment the present invention provides an air distributionapparatus comprising a manifold body, and a port defined through a wallof the manifold body. A delivery conduit is connected to the port, and aport valve is configured such that when the port valve is open thedelivery conduit is connected to an interior of the manifold bodythrough the port, and such that when the port valve is closed, thedelivery conduit is disconnected from the interior of the manifold body.A supply conduit is connected at an output end thereof to the interiorof the manifold body, and is connected at an input end thereof toreceive a product air stream with agricultural products entrainedtherein. The supply conduit extends substantially vertically up from themanifold body to a curved elbow and then extends substantiallyhorizontally from the elbow. An exhaust orifice is defined in the elbowat an inner radius of the elbow, and an exhaust valve is configured suchthat when the exhaust valve is open, a selected flow of pressurized airflows from an interior of the supply conduit through the exhaustorifice, and such that when the exhaust valve is closed, pressurized airfrom the interior of the supply conduit is prevented from flowingthrough the exhaust orifice. The port valve and exhaust valve arecontrolled such that when the port valve closes, the exhaust valveopens.

In a second embodiment the present invention provides an airdistribution manifold apparatus comprising a manifold body, and a portdefined through a wall of the manifold body. A delivery conduit isconnected to the port, and a port valve is configured such that when theport valve is open the delivery conduit is connected to an interior ofthe manifold body through the port, and such that when the port valve isclosed, the delivery conduit is disconnected from the interior of themanifold body. A supply conduit is connected at an output end thereof tothe interior of the manifold body, and is connected at an input endthereof to receive a product air stream with agricultural productsentrained therein. An exhaust conduit is connected at an input endthereof to receive a clean air stream with substantially no agriculturalproducts entrained therein, and connected at an output end thereof tothe delivery conduit in proximity to the port. An exhaust valve isconfigured such that when the exhaust valve is open, the deliveryconduit is connected to the exhaust conduit, and such that when theexhaust valve is closed, the delivery conduit is disconnected from theexhaust conduit. The port valve and exhaust valve are controlled suchthat when the port valve closes, the exhaust valve opens.

In a third embodiment the present invention provides a method ofcontrolling delivery of an agricultural product to a selected section offurrow openers of an air seeder. The method comprises, for each airseeder section providing a delivery conduit connected at an output endthereof to deliver the agricultural product to the section of furrowopeners, and connected at an input end thereof to a port defined througha wall of a manifold body; connecting an output end of a supply conduitto an interior of the manifold body, and directing a product air streamwith the agricultural product entrained therein into an input end of thesupply conduit such that the agricultural product moves through thesupply conduit, the manifold body, the ports, and the delivery conduitsto each section of furrow openers; closing a selected port to stop thedelivery of the agricultural product to the selected section of furrowopeners, and exhausting a selected flow of pressurized air from thesupply conduit; stopping exhausting the selected flow of pressurized airfrom the supply conduit and opening the selected port to restart thedelivery of the agricultural product to the selected section of furrowopeners.

The present invention thus maintains air speed above the criticalvelocity in the distribution network as ports are closed and opened, andcan also clear agricultural products from delivery conduits andmanifolds downstream of a closed or blocked port.

DESCRIPTION OF THE DRAWINGS

While the invention is claimed in the concluding portions hereof,preferred embodiments are provided in the accompanying detaileddescription which may be best understood in conjunction with theaccompanying diagrams where like parts in each of the several diagramsare labeled with like numbers, and where:

FIG. 1 is a schematic cutaway side view of an embodiment of an airdistribution apparatus of the present invention with the port valvesopen and the exhaust valves closed;

FIG. 2 is a schematic cutaway side view of the embodiment of FIG. 1 withone port valve closed and one exhaust valve open;

FIG. 3 is a schematic front view of an alternate exhaust valve for usewith the embodiment of FIG. 1;

FIG. 4 is a schematic cutaway side view of an embodiment of an airdistribution apparatus of the present invention where the exhaust isconnected to and directed into the delivery conduits, and shown with theport valves open and the exhaust valves closed;

FIG. 5 is a schematic cutaway side view of the embodiment of FIG. 4 withone port valve closed and one exhaust valve open such that exhaust airis directed through the delivery conduit;

FIG. 6 is a schematic top view of the manifold body of the embodiment ofFIG. 1;

FIG. 7 is a schematic side view of an embodiment of an air distributionmanifold apparatus of the present invention where the supply conduitextends vertically down from the manifold body, and wherein the cleanair stream is obtained at a remote source such as directly from the airseeder fan or an auxiliary fan;

FIG. 8 is a schematic cutaway side view a valve body for use with theembodiment of FIG. 4 where the port valve and exhaust valve areconnected together such that when one opens the other closes, and viceversa;

FIG. 9 is a schematic top view of an air seeder showing field stripsseeded by furrow openers in adjacent sections of furrow openers;

FIG. 10 is a schematic top view of an embodiment of an air distributionmanifold apparatus of the present invention where the manifold is aninline flat fan type manifold;

FIG. 11 is a perspective view of an air distribution manifold apparatusof the present invention with plunger type valves;

FIG. 12 is a cutaway view of the valve body of the embodiment of FIG. 12with the port valve closed and the exhaust valve open;

FIG. 13 is a cutaway view of the valve body of the embodiment of FIG. 12with the port valve open and the exhaust valve closed.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

FIGS. 1 and 2 schematically illustrate an embodiment of an airdistribution apparatus 1 of the present invention. The apparatus 1 isshown as part of an air seeder product distribution network. Theapparatus 1 comprises a manifold body 3 comprising substantiallycircular top and bottom plates 5, as illustrated in FIG. 6, orientedsubstantially horizontally, and a substantially vertical body wall 7extending between the top and bottom plates 5A, 5B. Ports 9 are definedthrough the body wall 7, and a delivery conduit 11 is connected to eachport 9.

A port valve 13 is configured such that when the port valve 13 is open,as illustrated in FIG. 1, the delivery conduit 11 is connected to theinterior of the manifold body 3 through the port 9, and such that whenthe port valve 13 is closed, as illustrated in FIG. 2, the deliveryconduit 11 is disconnected from the interior of the manifold body 3.

A substantially vertically oriented supply conduit 15 is connected at anoutput end 15A thereof to the interior of the manifold body 3 through anaperture 17 in the top plate 5A. The supply conduit 15 extendssubstantially vertically up from the manifold body 3 to a curved elbow19 and then extends substantially horizontally from the elbow 19 to aninput end 15B thereof that is connected to receive a product air streamAS with agricultural products 21 entrained therein. The product airstream AS is provided by a conventional air seeder fan and meteringsystem.

An exhaust orifice 33 is defined in the elbow 19 at an inner radius ofthe elbow 19. An exhaust valve 25 is configured such that when theexhaust valve 25 is open, as schematically illustrated in FIG. 2, aselected flow of pressurized air PA flows from an interior of the supplyconduit 15 through the exhaust orifice 33. When the exhaust valve 25 isclosed, as schematically illustrated in FIG. 1, pressurized air from theinterior of the supply conduit 15 is prevented from flowing through theexhaust orifice 33. The port valve 13 and exhaust valve 25 arecontrolled such that when the port valve 13 closes, the exhaust valve 25opens.

In operation when seeding, agricultural products are carried in the airstream AS from the tanks carrying various seed, fertilizer, and/ormixtures of same or like products. The air stream AS and entrainedproducts enter the manifold body 3 which is designed so thatsubstantially equal portions of the air stream AS and agriculturalproducts exit through each port 9 into the delivery conduits 11 and, inthe illustrated apparatus, to a secondary manifold 27 which againdivides the air stream AS and entrained agricultural productssubstantially equally to each secondary delivery conduit 29 and then tothe furrow openers 31.

When it is desired to turn off the flow of agricultural products 21 tothe secondary manifold 27, the port valve 13 is closed, and one of theexhaust valves 25 is opened by a controller 35. The closing of the portvalve 13 will typically be triggered by an operator who has visuallydetermined that the furrow openers 31 fed by the secondary manifold 27are passing through previously seeded soil, or by a global positioningsystem GPS which has determined the same thing. The air flow in thedelivery conduit 11 and downstream from there stops when the port valve13 closes, and at the same time the exhaust valve 25 opens.

The size of the exhaust orifice 33 is typically configured such that theselected flow of pressurized air PA flowing through the exhaust orifice33 when the exhaust valve 25 is open is substantially the same as anamount of air flowing through the port 9 when the port valve 13 is open.Thus the volume of air flow through the supply conduit 15 upstream fromthe elbow 19 is maintained at about the same amount whether the portvalve 13 is open or closed, and critical velocity of the product airstream AS will be maintained to prevent agricultural products fromfalling out of the air stream.

In the illustrated apparatus 1, the exhaust orifices 33 are defined inthe wall of the elbow 19 that forms the inner radius of the elbow 19. Ithas been found that a clean air stream, with substantially noagricultural products entrained therein, can be drawn off the productcarrying air stream AS at the inner radius since the agriculturalproducts 21 follow the outer radius of the elbow 19 when making the turnfrom the horizontal to the vertical direction. Thus the selected flow ofpressurized air PA can be drawn out of the supply conduit without losingany product 21.

In the illustrated apparatus 1 as well, the supply conduit 15 extendsvertically down from the elbow 19 to the manifold body 3. It can be seenthat as pressurized air is drawn off at the elbow 19 through one or moreof the exhaust orifices 33, less air is moving through the verticalportion of the supply conduit 15. With the product air stream AS movingdownward, the reduced volume of air in the air stream AS does notadversely affect the movement of the entrained product to the manifold 3as same is drawn down by gravity.

The apparatus 1 comprises first and second ports 9A, 9B, first andsecond delivery conduits 11A, 11B, and first and second port valves 13A,13B connecting the corresponding first and second delivery conduits 11A,11B to the first and second ports 9A, 9B. First and second exhaustorifices 33A, 33B are defined in the inner radius of the elbow 19, andcorresponding first and second exhaust valves 25A, 25B for stopping andstarting the flow of pressurized air flows from the interior of thesupply conduit 15 through the corresponding first and second exhaustorifices 33A, 33B.

The first port valve 13A and first exhaust valve 25A can be controlledsuch that when the first port valve 13A closes, the first exhaust valve25A opens, and in the same manner when the second port valve 13B closes,the second exhaust valve 25B opens. The selected flow of pressurized airPA flowing through the exhaust orifices 33A, 33B when the first andsecond exhaust valves 25A, 25B are open is substantially the same as anamount of air flowing through the first and second ports 9A, 9B when thecorresponding first and second port valves 13A, 13B are open.

Where, as is typical, a manifold includes six to eight ports, an exhaustorifice and valve can be provided for each port.

Alternatively a single adjustable exhaust valve 25′ can be provided asschematically illustrated in FIG. 3. In a system with the exhaust valve25′, the first and second port valves 13A, 13B and the exhaust valve 25′are controlled such that when the first or the second port valve closes,the exhaust valve 25′ opens to a first degree, illustrated by the dottedline D1 such that a first selected flow of pressurized air,substantially equal to the amount of air flowing through one of theports when one port valve is open, flows from the inner radius of theelbow 19′ of the supply conduit through the exhaust orifice 33′. Whenboth the first and the second port valves 13A, 13B close, the exhaustvalve 25′ opens to a second degree, illustrated by dotted line D2, suchthat a second selected flow of pressurized air flows from the supplyconduit through the exhaust orifice 33′ that is substantially the sameas the amount of air flowing through the first and second ports when thefirst and second port valves 13A, 13B are open. Where further ports areprovided, further opening of the exhaust valve 25′ can be provided aswell.

Thus the velocity of the air stream AS in the horizontal portion of thesupply conduit is maintained above the critical velocity. In theapparatus 1, the exhaust orifice 33 is open to the atmosphere, such thatpressurized air PA from the interior of the supply conduit 15 flowsthrough the exhaust orifice 33 into the atmosphere when the exhaustvalve 25 is open.

As illustrated in the apparatus 1′ of FIGS. 4 and 5, an exhaust conduit23 can be connected at an input end 23A thereof to the exhaust orifice33 and with an output end 23B thereof connected to an exhaustdestination, such that the selected flow of pressurized air PA flowsthrough the exhaust conduit 23. The exhaust destination can be selectedto suit the particular circumstances, however beneficially in theapparatus 1′, the exhaust conduit 23 is connected at the output end 23Bthereof to the delivery conduit 11 in proximity to the port 9. Althoughthe exhaust valve could remain on the exhaust orifice 33 at the inputend 23A of the exhaust conduit 23, in the illustrated apparatus 1′, theexhaust valve 25′ is moved to the output end of the exhaust conduit 23to facilitate mounting the port valve 13 and exhaust valve 25 in a valveassembly as described further below.

Thus when the port valve 13 is closed and the exhaust valve 25′ is open,as illustrated in FIG. 5, the delivery conduit 11 is connected to theexhaust conduit 23 and the selected flow of pressurized air PA flowsthrough the exhaust conduit 23 into the delivery conduit 11. Thusinstead of the air flow in the delivery conduit 11 and downstream fromthere immediately stopping as in the prior art gated manifold ports,when the port valve 13 closes, the exhaust valve 25 opens such that aclean air stream, the pressurized air PA with substantially noagricultural products entrained therein, flows from the inner radius ofthe elbow 19 into the delivery conduit 11 and downstream through thesecondary manifold 27 and secondary delivery conduits 29.

Thus the velocity of the air stream AS through the supply conduit 15upstream from the elbow 19 is maintained and as well, agriculturalproducts remaining in the distribution network downstream from theblocked port are pushed out to the furrow openers 31 so that theproducts do not fall and block the conduits. When the exhaust valve 25′is closed, as illustrated in FIG. 4, the delivery conduit 11 isdisconnected from the exhaust conduit 23 and connected to the port toreceive the product air stream AS.

FIG. 7 schematically illustrates a further alternative embodiment with amanifold body 203, ports 209, port valves 213, delivery conduits 211,and supply conduit 215 where the exhaust conduits 223 are connected to aclean air stream CAS that is drawn off the distribution network at someearlier point where a clean air stream might be available, such asdirectly off the fan output prior to the meter, or from a separatepressurized air source altogether. When the port valve closes, theexhaust valve 225 opens and the clean air stream CAS flows through thedelivery conduit to clear agricultural products from any downstreamconduits, manifolds, and the like.

FIG. 8 schematically illustrates a convenient configuration comprising avalve assembly 337 connected to the port 309 of the manifold body 303,to the delivery conduit 311, and to the exhaust conduit 323. The portvalve 313 and the exhaust valve 325 are incorporated in the valveassembly 337 and are provided by butterfly type valves oriented at 90degrees and connected to a vertical shaft 339 that rotates at thecommand of the controller 335. The port valve 313 and exhaust valve 325are connected such that when the port valve 313 closes the exhaust valve325 opens, which is the position shown in FIG. 8. Then when the portvalve 313 opens, the exhaust valve 325 closes. A known plunger typevalve or other such valve as is known in the art could also be used toprovide a connected valve that operates as described.

An alternate manifold body 403 is schematically illustrated in FIG. 10.The manifold body 403 is a flat fan type manifold body where the supplyconduit 415 directs the product air stream AS into a first end of the aflat manifold body 403 which divides the product air stream AS intochannels 461 with the ports 409 at the ends of the channels 461 on asecond opposite end of the flat manifold body 403. An exhaust conduit423 is connected as described above to receive a clean air stream froman exhaust orifice at an upstream elbow, or from another source. A portvalve 413 and exhaust valve 425 control flow of either the product airstream AS or exhaust air stream PA to the delivery conduit 411 asdescribed above.

Thus the present invention provides an air stream exhaust to maintainair speed in the supply conduit above the critical velocity. Theexhausted air can also be directed into the delivery conduit of theclosed port to clear delivery conduits and manifolds downstream, or aseparate clean air stream can be directed into the delivery conduit.

A method is provided of controlling delivery of an agricultural productto a selected section of furrow openers 31 of an air seeder 51. In atypical practice of the method the product air stream AS is provided bya conventional air seeder fan and metering system mounted on an airseeder cart 55.

In the embodiment illustrated in FIG. 9, each section of furrow openerscomprises a secondary manifold 27 connected to a plurality of furrowopeners 31. The furrow openers 31 are spaced laterally across a frame 53such that all the furrow openers fed by one secondary manifold 27 arelaterally spaced from the furrow openers fed by an adjacent secondarymanifold 27 such that the furrow openers of one section seed a fieldstrip F1, while the furrow openers fed by an adjacent secondary manifold27 seed an adjacent field strip F2. Thus as the strip of field areanarrows to a width less than the air seeder 51, the flow of agriculturalproducts is directed to selected sections of furrow openers 31 to seedany one or all of field strips F1, F2, F3, F4.

Alternatively each “section” of furrow openers could comprise a singlefurrow opener fed from a secondary manifold with port and exhaust valves13, 25 controlling the flow of the product air stream AS to each singlefurrow opener.

As shown in the accompanying drawings, the method comprises for each airseeder section providing a delivery conduit 11 connected at an outputend thereof to deliver the agricultural product to the section of furrowopeners 31, and connected at an input end thereof to a port 9 definedthrough a wall of a manifold body 3; connecting an output end of asupply conduit 15 to an interior of the manifold body 3, and directing aproduct air stream AS with the agricultural product 21 entrained thereininto an input end of the supply conduit 15 such that the agriculturalproduct moves through the supply conduit 15, the manifold body 3, theports 9, and the delivery conduits 11 to each section of furrow openers31; closing a selected port 9 to stop the delivery of the agriculturalproduct 21 to a selected section of furrow openers 31 and exhausting aselected flow of pressurized air PA from the supply conduit 15; stoppingexhausting the selected flow of pressurized air PA from the supplyconduit 15 and opening the selected port 9 to restart the delivery ofthe agricultural product to the selected section of furrow openers 31.

To avoid exhausting agricultural products entrained in the product airstream, the air seeder is configured such that the supply conduit 15extends substantially vertically up from the manifold body 3 to a curvedelbow 19 and then extends substantially horizontally from the elbow 19,and the selected flow of pressurized air PA is exhausted from the supplyconduit 15 through an exhaust orifice 33 defined in the elbow 19 at aninner radius of the elbow 19.

The selected port 9 is closed by providing a port valve 13 configuredsuch that when the port valve 13 is open the delivery conduit 11 isconnected to an interior of the manifold body 3 through the port 9, andsuch that when the port valve 13 is closed, the delivery conduit 11 isdisconnected from the interior of the manifold body 3.

The delivery conduits may be cleared of agricultural products byconnecting the exhaust orifice 33 to the delivery conduit 11 inproximity to the input end thereof such that the selected flow ofpressurized air PA from the supply conduit 15 passes through thedelivery conduit 11.

FIGS. 11-13 illustrate an air distribution manifold apparatus 501 thatcomprises a manifold body 503 with output ports 509, and a valveassembly 537 connected to each port 509. A substantially verticallyoriented supply conduit 515 is connected at an output end 515A thereofto the interior of the manifold body 503. The supply conduit 515 extendssubstantially vertically up from the manifold body 503 to a curved elbow519 and then extends substantially horizontally from the elbow 519 to aninput end 515B thereof that is connected to receive a product air streamAS with agricultural products entrained therein.

A delivery conduit 511, and an exhaust conduit 523 are connected to eachvalve body 537. Only one of each is shown to allow for betterillustration. The exhaust conduits 523 are connected to exhaust orifices533 at the inner radius of the elbow 519, and the delivery conduits 511are connected to downstream manifolds or furrow openers. The port valve513 and the exhaust valve 525 are incorporated in the valve assembly 537and are provided by a plunger type valve where the valve element 541provides both the port valve 513 and exhaust valve 525. When the valveelement 541 is in the position shown in FIG. 12 the port 509 is blockedby the valve element 541 and the port valve 513 is thus closed, and theexhaust conduit 523 is connected to the delivery conduit 511 and theexhaust valve 525 is thus open. Then when, in response to a controlsignal, the valve element 541 moves to the position shown in FIG. 13,the port 509 is connected to the delivery conduit 511 and the port valve513 is thus open, while the passage from the exhaust conduit 523 to thedelivery conduit 511 is blocked by the valve element and the exhaustvalve 525 is thus closed.

As described above, when the port valve 513 is closed, and the exhaustvalve 525 is open, as illustrated in FIG. 12, the delivery conduit 511is disconnected from the interior of the manifold body 503 and isconnected to the clean air stream from the exhaust orifice 533 at theelbow 519, such that clean air flows through the delivery conduit 511.When the port valve 513 is open, and the exhaust valve 525 is closed, asillustrated in FIG. 13, the delivery conduit 511 is connected to theinterior of the manifold body 503 and the product bearing air stream ASflows through the delivery conduit 511, and no air flows through theexhaust conduit 523.

As ports are opened and closed the rate of metering agriculturalproducts into the product air stream is adjusted accordingly. Thepresent invention maintains critical velocity of air flow through thedistribution network and can also ensure that delivery conduits and/ormanifolds downstream from a closed port are clear.

The foregoing is considered as illustrative only of the principles ofthe invention. Further, since numerous changes and modifications willreadily occur to those skilled in the art, it is not desired to limitthe invention to the exact construction and operation shown anddescribed, and accordingly, all such suitable changes or modificationsin structure or operation which may be resorted to are intended to fallwithin the scope of the claimed invention.

1. An air distribution apparatus comprising: a manifold body, and a portdefined through a wall of the manifold body; a delivery conduitconnected to the port; a port valve configured such that when the portvalve is open the delivery conduit is connected to an interior of themanifold body through the port, and such that when the port valve isclosed, the delivery conduit is disconnected from the interior of themanifold body; a supply conduit connected at an output end thereof tothe interior of the manifold body, and connected at an input end thereofto receive a product air stream with agricultural products entrainedtherein; wherein the supply conduit extends substantially vertically upfrom the manifold body to a curved elbow and then extends substantiallyhorizontally from the elbow; an exhaust orifice defined in the elbow atan inner radius of the elbow, and an exhaust valve configured such thatwhen the exhaust valve is open, a selected flow of pressurized air flowsfrom an interior of the supply conduit through the exhaust orifice, andsuch that when the exhaust valve is closed, pressurized air from theinterior of the supply conduit is prevented from flowing through theexhaust orifice; wherein the port valve and exhaust valve are controlledsuch that when the port valve closes, the exhaust valve opens.
 2. Theapparatus of claim 1 wherein the exhaust orifice is open to atmosphere,such that pressurized air from the interior of the supply conduit flowsthrough the exhaust orifice into the atmosphere when the exhaust valveis open.
 3. The apparatus of claim 1 comprising an exhaust conduitconnected at an input end thereof to the exhaust orifice and with anoutput end thereof connected to an exhaust destination, such that theselected flow of pressurized air flows through the exhaust conduit. 4.The apparatus of claim 3 wherein the output end of the exhaust conduitis connected to the delivery conduit such that the selected flow ofpressurized air flows through the delivery conduit.
 5. The apparatus ofclaim 4 comprising a valve assembly connected to the port, the deliveryconduit, and the exhaust conduit, and wherein the port valve and theexhaust valve are incorporated in the valve assembly.
 6. The apparatusof claim 5 wherein the port valve and exhaust valve are connected suchthat when the port valve closes the exhaust valve opens, and such thatwhen the port valve opens the exhaust valve closes.
 7. The apparatus ofclaim 1 wherein a size of the exhaust orifice is configured such thatthe selected flow of pressurized air flowing through the exhaust orificewhen the exhaust valve is open is substantially the same as an amount ofair flowing through the port when the port valve is open.
 8. Theapparatus of claim 1 wherein the delivery conduit is connected at anoutput end thereof to a secondary manifold.
 9. The apparatus of claim 1comprising: first and second ports defined through a wall of themanifold body; first and second delivery conduits connected tocorresponding first and second ports; first and second port valvesconnecting the corresponding first and second delivery conduits to thefirst and second ports; first and second exhaust orifices defined in theelbow at an inner radius of the elbow, and corresponding first andsecond exhaust valves for stopping and starting the flow of pressurizedair flows from the interior of the supply conduit through thecorresponding first and second exhaust orifices; wherein the first portvalve and first exhaust valve are controlled such that when the firstport valve closes, the first exhaust valve opens; wherein the secondport valve and second exhaust valve are controlled such that when thesecond port valve closes, the second exhaust valve opens.
 10. Theapparatus of claim 9 wherein the selected flow of pressurized airflowing through the exhaust orifice when the first exhaust valve is openis substantially the same as an amount of air flowing through the firstport when the first port valve is open.
 11. The apparatus of claim 9comprising first and second exhaust conduits connected at input endsthereof to corresponding first and second exhaust orifices, andconnected at output ends thereof to corresponding first and seconddelivery conduits.
 12. The apparatus of claim 1 comprising: first andsecond ports defined through a wall of the manifold body; first andsecond delivery conduits connected to corresponding first and secondports; first and second port valves connecting the corresponding firstand second delivery conduits to the first and second ports; wherein thefirst and second port valves and the exhaust valve are controlled suchthat when the first or the second port valve closes, the exhaust valveopens to a first degree such that a first selected flow of pressurizedair flows from an interior of the supply conduit through the exhaustorifice, and such that when the first and the second port valve close,the exhaust valve opens to a second degree such that a second selectedflow of pressurized air flows from an interior of the supply conduitthrough the exhaust orifice.
 13. The apparatus of claim 12 wherein thefirst selected flow of pressurized air flowing through the exhaustorifice is substantially the same as an amount of air flowing throughthe first or second port when the corresponding first or second portvalve is open, and wherein the second selected flow of pressurized airflowing through the exhaust orifice is substantially the same as anamount of air flowing through the first and second ports when thecorresponding first and second port valves are open.
 14. An airdistribution manifold apparatus comprising: a manifold body, and a portdefined through a wall of the manifold body; a delivery conduitconnected to the port; a port valve configured such that when the portvalve is open the delivery conduit is connected to an interior of themanifold body through the port, and such that when the port valve isclosed, the delivery conduit is disconnected from the interior of themanifold body; a supply conduit connected at an output end thereof tothe interior of the manifold body, and connected at an input end thereofto receive a product air stream with agricultural products entrainedtherein; an exhaust conduit connected at an input end thereof to receivea clean air stream with substantially no agricultural products entrainedtherein, and connected at an output end thereof to the delivery conduitin proximity to the port; an exhaust valve configured such that when theexhaust valve is open, the delivery conduit is connected to the exhaustconduit, and such that when the exhaust valve is closed, the deliveryconduit is disconnected from the exhaust conduit; wherein the port valveand exhaust valve are controlled such that when the port valve closes,the exhaust valve opens.
 15. The apparatus of claim 14 wherein themanifold body comprises substantially circular top and bottom platesoriented substantially horizontally, and a substantially vertical bodywall extending between the top and bottom plates, and wherein the portis defined through the body wall.
 16. The apparatus of claim 15 whereinthe supply conduit is oriented substantially vertically and is connectedat the output end thereof to the interior of the manifold body throughan aperture in one of the top and bottom plates.
 17. The apparatus ofclaim 14 wherein the manifold body is a flat fan type manifold bodywhere the supply conduit directs the product air stream into a first endof the a flat manifold body which divides the product air stream intochannels with the ports at the ends of the channels on a second oppositeend of the flat manifold body.
 18. The apparatus of claim 14 wherein thesupply conduit extends substantially vertically up from the manifoldbody to a curved elbow and then extends substantially horizontally fromthe elbow, and wherein the exhaust conduit is connected at the input endthereof to the supply conduit at an inner radius of the elbow.
 19. Theapparatus of claim 14 comprising a valve assembly connected to the port,the delivery conduit, and the exhaust conduit, and wherein the portvalve and the exhaust valve are incorporated in the valve assembly. 20.The apparatus of claim 19 wherein the port valve and exhaust valve areconnected such that when the port valve closes the exhaust valve opens,and such that when the port valve opens the exhaust valve closes. 21.The apparatus of claim 14 wherein the delivery conduit is connected atan output end thereof to one of a furrow opener and a secondarymanifold.
 22. A method of controlling delivery of an agriculturalproduct to a selected section of furrow openers of an air seeder, themethod comprising: for each air seeder section providing a deliveryconduit connected at an output end thereof to deliver the agriculturalproduct to the section of furrow openers, and connected at an input endthereof to a port defined through a wall of a manifold body; connectingan output end of a supply conduit to an interior of the manifold body,and directing a product air stream with the agricultural productentrained therein into an input end of the supply conduit such that theagricultural product moves through the supply conduit, the manifoldbody, the ports, and the delivery conduits to each section of furrowopeners; closing a selected port to stop the delivery of theagricultural product to the selected section of furrow openers, andexhausting a selected flow of pressurized air from the supply conduit;stopping exhausting the selected flow of pressurized air from the supplyconduit and opening the selected port to restart the delivery of theagricultural product to the selected section of furrow openers.
 23. Themethod of claim 22 wherein the supply conduit extends substantiallyvertically up from the manifold body to a curved elbow and then extendssubstantially horizontally from the elbow and wherein the selected flowof pressurized air is exhausted from the supply conduit through anexhaust orifice defined in the elbow at an inner radius of the elbow.24. The method of claim 23 wherein the selected port is closed byproviding a port valve configured such that when the port valve is openthe delivery conduit is connected to an interior of the manifold bodythrough the port, and such that when the port valve is closed, thedelivery conduit is disconnected from the interior of the manifold body.25. The method of claim 24 comprising connecting the exhaust orifice tothe delivery conduit in proximity to the input end thereof such that theselected flow of pressurized air from the supply conduit passes throughthe delivery conduit.
 26. The method of claim 22 wherein the selectedsection of furrow openers comprises one of a secondary manifoldconnected to a plurality of furrow openers and a single furrow opener.